A hybrid vehicle is a railway vehicle that is configured to use a generator to convert an engine output into electric power and to drive an electric motor using the electric power from the generator and electric power from a power storage device such as a battery so as to control the propulsion of the vehicle.
In the hybrid vehicle configured as described above, which has been disclosed, for example, in Patent Literature 1, a DC-voltage command value for a DC bus is set on the basis of the target output of the battery and the charging rate of the battery, with the output from the battery to the DC bus controlled so as to reach the target output; and when the output from the battery to the DC bus reaches the target output, the output from the generator is controlled such that the DC-voltage level of a converter approaches the DC-voltage command value. The contents of Non Patent Literature 1 mentioned below are described later.